Estimation of RF voltage on the ion trap through a capacitive voltage divider

Three-dimensional confinement of charge particles within a radiofrequency (RF) ion trap is achieved using an oscillating electric field (RF) along with the static field. The combination of DC and the RF field provides the force gradient to confine the ion to the saddle point of the quadrupole shaped spatial distribution of the electric field. Helical resonators are commonly used for efficient delivery of high voltage RF to the trap electrode. In order to achieve better control on the trapped ions, its essential to know the amplitude of the RF voltage being delivered at trap electrodes. This article describes the design and development of a capacitive voltage divider circuit for analyzing high voltage RF being delivered to the ion trap through a helical resonator. The voltage divider is connected parallel to the ion trap to access a minor fraction of voltage being delivered at the trap electrodes (with a ratio of 1:1000) to detect the value of high voltage being delivered to the ion trap.